Control apparatus for a machine for stacking boards or the like

ABSTRACT

A control apparatus for a stacking machine for boards of regular and irregular shape, comprising (a) means which produce an electrical pulse for each unit of displacement path of the boards transversely with respect to their lengthwise direction; (b) two pre-selection pulse counters which can be reset to null; (c) scanning or feeler switch means which permit the infeed of the generated pulses to both pre-selection pulse counters during passage of the boards past a scanning location; (d) an operable connection between both pre-selection pulse counters so that during one working cycle one such pre-selection pulse counter functions as an adding counter mechanism and the other as a storage counter mechanism, in that after interrupting the infeed of the pulses - which is comparable to the throughpassage of the rear edge of a board past the scanning location - the other of such pre-selection pulse counters is reset to null, and specifically until the adding counter mechanism has attained a pre-selected pulse number, wherein at the moment of reaching such pre-selected pulse number (di) both pulse counters are switched so that from that moment on the storage counting mechanism functions as an adding counter mechanism and the adding counter mechanism functions as a storage counter mechanism, so that the combination of both such counters is prepared for the measurements in the next working cycle, (dii) a relay is actuated which at a follow-up or sequence control mechanism triggers a first operation of a logical sequence of working operations of the stacking machine.

United States Patent [1 1 Balz [ CONTROL APPARATUS FOR A MACHINE FOR STACKING BOARDS OR THE LIKE [76] Inventor: Rudolf Balz, Napfstrasse 33,

3550 Langnau, Switzerland 22 Filed: Jan. 26, 1973 21 Appl. No.: 327,131

[30] Foreign Application Priority Data Feb, 1, 1972 Switzerland 1439/72 [52] US. Cl. 317/157, 307/149 [5 1] Int. Cl A0lh 47/00 [58] Field of Search 317/142 R, 157; 307/149 [56] References Cited UNITED STATES PATENTS 3,154,726 10/1964 McClain ..3l7/l42R Primary Examiner-L. T. l-lix Attorney, Agent, or FirmWemer W. Kleeman [5 7] ABSTRACT A control apparatus for a stacking machine for boards of regular and irregular shape, comprising (a) means which produce an electrical pulse for each unit of displacement path of the boards transversely with respect 111 3,793,568 Feb. 19, 1974 to their lengthwise direction; (b) two preselection pulse counters which can be reset to null; (c) scanning or feeler switch means which permit the infeed of the generated pulses to both pre-selection pulse counters during passage of the boards pasta scanning location; ((1) an operable connection between both preselection pulse counters so that during one working cycle one such pre-selection pulse counter functions as an adding counter mechanism and the other as a storage counter mechanism, in that after interrupting the infeed of the pulses which is comparable to the throughpassage of the rear edge of a board past the scanning location the other of such pre-selection pulse counters is reset to null, and specifically until the adding counter mechanism has attained a preselected pulse number, wherein at the moment of reaching such pre-selected pulse number (di) both pulse counters are switched so that from that moment on the storage counting mechanism functions as an adding counter mechanism and the adding counter mechanism functions as a storage counter mechanism, so that the combination of both such counters is prepared for the measurements in the next working cycle, (dii) a relay is actuated which at a follow-up or sequence control mechanism triggers a first operation of a logical sequence of working operations of the stacking machine.

1 Claim, 8 Drawing Figures PATENTEUFEBIBIQH 3.793.568

sum 3 or 4 13 A B 11. c 13 140 100 105 100 105 n A y 1s 10 no FIGA FIG.5

FIG.7

PATENTEUFEBI 9 m4 SHEET l 0! 4 ggw CONTROL APPARATUS FOR A MACHINE FOR STACKING BOARDS OR THE LIKE BACKGROUND OF THE INVENTION intended to be transported, or if possibly for other purposes there should be tied about the stack a steel band for securing and binding the boards, then the stack must be as compact as possible, that is to say, the boards should be placed upon one another without any intermediate spaces. However, if the boards are to be air dried or dried in a furnace then a number of ledges should be placed transversely upon the individual layers of such boards within the stack so that the air can circulate over the layers of such boards, yet the stack itself must still possess good stability. With automatic stacking of random width boards while building stack layers of uniform width there is present the difficulty of determining whether a certainboard still has place in a stack layer.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a control apparatus for solving this problem.

Another and more specific object of the present invention relates to a new and improved construction of control apparatus for machines for stacking boards and which is extremely reliable in operation, relatively uncomplicated in design, economical to manufacture, and requires a minimum of servicing and maintenance.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the inventive control apparatus is manifested by the features that there are provided:

a means which produce an electrical pulse for each unit of displacement path of the boards transversely with respect to their lengthwise direction;

b two pre-selection pulse counters which can be reset to null;

c scanning or feeler switch means which permit the infeed of the generated pulses to both pre-selection pulse counters during passage of the boards past a scanning location;

d an operable connection between both pre-selection pulse counters so that during one working cycle one such preselection pulse counter functions as an adding counter mechanism and the other as a storage counter mechanism, in that after interrupting the infeed of the pulses which is comparable to the throughpassage of the rear edge of a board past the scanning location the other of such pre-selection pulse counters is reset to null, and specifically until the adding counter mechanism has attained a pre-selected pulse number,

wherein at the moment of reaching such pre-selected pulse number i both pulse counters are switched so that from that moment on the storage counting mechanism functions as an adding counter mechanism and the adding counter mechanism functions as a storage counter mechanism, so that the combination of both such counters is prepared for the measurements in the next working cycle,

ii a relay is actuated which at a follow-up or sequence control mechanism triggers a first operation of a logical sequence of working operations of the stacking machine.

According to a particular manifestation of the invention such control mechanism can be further constructed in a manner that it also can be employed to control means by virtue of which there can be achieved the result that the outermost boards located in a stack are aligned such that their outer edges extend parallel to the lengthwise axis of the stack.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be betterunderstood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein there is shown an exemplary embodiment of control apparatus and schematically also a stacking machine with which such control apparatus is employed, and specifically wherein;

FIG. 1 is a perspective schematic view of the stacking machine;

,FIG. 2 is a schematic partial elevational view of the arrangement of FIG. 1, in which there have been depicted components of the control apparatus;

FIG. 3 is a partial side elevational view of the arrangement of FIG. 2 depicting a pulse transmitter which is part of the control apparatus;

FIGS. 4, 5, 6 and 7 are respective schematic elevational views, similar to the showing of FIG. 2, depicting different successive operational or functional phases of the equipment; and

FIG. 8 is an electrical circuit diagram of the control apparatus.

DETAILED DESCRIPTIONOF THE PREFERRED EMBODIMENTS Describing now the drawings, in the illustrated exemplary embodiment of stacking machine boards or planks 100, hereinafter simply conveniently referred to as boards, are either placed by hand or automatically, for instance by means of separation mechanism, upon rollers 101 of a lengthwise transporting mechanism T. By means of these rollers 101 the boards are conveyed up to the location of a stop 102 which, through the agency of a terminal switch 103, places into operation a non-illustrated motor drive of transverse conveying chains 104,. By means of the stop l02'there'is attained the result that all of the boards 100 are conveyed to the same extent in the Y-direction so that their end faces or ends which are situated forwardly in the lengthwise conveying direction are aligned at one end of the pile or stack. The transverse conveying chains 104 are provided with conveying cams or dogs 105 located at a regular or uniform spacing from one another. These conveying cams 105 laterally withdraw each board from the rollers 101, so that each such board extends with its lengthwise edge which is located rearwardly with respect to the conveying direction parallel to the Y-direction, that is to say, with respect to the lengthwise axis of the stack 11].

During such conveying of the boards 100 by the chains 104 and the associated cams 105 each board actuates a feeler flap or tongue member 14a of a switch 14 of the particular measuring-and control apparatus which is provided. There can be arranged a number of such switches electrically connected in parallel behind one another in the Y-direction or there can be actuated a single switch 14 by means of a flap or tongue member 14a which extends over all of the conveying chains 104. The construction and the mode of operation of the particularly provided measuringand control apparatus will be described in greater detail hereinafter.

Now as soon as a given board arrives at the forwardmost sector A of the machine it is then deposited, in a manner to be more fully described hereinafter, upon support or carrier arms 106 which are displaceable parallel to the conveyor chains 104. If one is concerned with a board which, in the direction of conveying of the chains 104, should come to lie forwardmost in'a stack position, in other words at the right side (FIG. 1) of the stack which is in the process of being formed, then, by means of the control mechanism presses or pressure members 107 are now placed into operation. These presses 107 lower a stop or impact beam 108 down to a location which is quite close to the carrier or support arms 106. Furthermore, presses 109 are placed into operation which press such board against the stop beam 108 so that its forwardmost lengthwise edge is aligned with respect to the Y-direction. As soon as this procedure has occurred then the presses 107 and 109 are again retracted back into their rest position and the further advance of the conveyor chains 104 is again switched-in, and which chains previously were switched-out during such aligning operation.

During their further transverse conveying by the chains 104 the boards actuate the feeler flap members or feeler tongues 13a of a switch 13. This switch 13ensures that now the carrier or support arms 106 are advanced with the same speed as the transverse conveying chains 104 in their conveying direction. The displacement movement occurs for such length of time until the terminal switch 13 has sensed that the board has just completely moved therepast. After such displacement has been terminated the transverse conveying chains 104 continue to move and advance the next board, which bears by means of its lengthwise edge which trails in the conveying direction against the cams 105 and therefore is aligned with such edge in the Y- direction, until such board moves beneath the switch 13 and its feeler flap member 13a respectively. Again the carrier or support arms 106 are extended in accordance with the board width. This procedure repeats for such length of time until the hereinafter to be described measuring and control apparatus determines that the next board, which at that moment is located at the region or sector A, still has place in the stack, yet however the second next board, which is still located in sector B, no longer has space in the stack. In order that such board, which still has space in the stack, can be stacked such that its rear edge is placed flush with respect to the existing stack edge, the carrier arms 106 are extended into a fixed position, terminal position 1. This terminal position 1 is that location where there has been completed conveying of the boards by the transverse conveying cams, because such cams upon passing the deflecting rollers are lowered. The transverse conveying cams 105 now transport the last board ofa stack layer to the support arms 106,whereby the switch 13 is now bridged and there is not carried out any additional feed or advancing movement of the support arms 106. There has now been deposited a complete layer of boards upon the support arms 106. The spacing of the boards can be increased or decreased by a device provided at the feeler flap member 13a of the switch 13. There is now placed out of operation the drive of the transverse conveyor chains 104, and the support arms 106 are extended until they reach their outermost terminal position ll.

Thereafter, the stack 111 is raised by means of a lifting mechanism 116 in such a manner beneath the carrier arms 106 that such are no longer contacted. The end or terminal position of the lifting'movement is controlled by feeler or scanning ledges 112 which are provided at the carrier or support arms and which cooperate with an associated terminal switch. At the same time pin or nail ledges 113 i.e., ledges or strips with pins and a transverse rod magazine 114 arranged over the ity a number of such devices are arranged in tandem in the Y-direction. At the nail ledges 113 there are freely displaceably guided vertical upstanding pins 115 in such a way that they tend to fall down under the action of their own weight. A thickened or enlarged portion provided at the head of each of the pins 115 prevents them from dropping out. Lowering of the nail ledge 113 and the transverse rod magazine 114 occurs up to a point directly adjacent the boards 100 which have been deposited upon the carrier or support arms 106. The degree of lowering is controlled by adjusting a feeler or scanner ledge which, for instance, is mounted at the'bottom at one of the transverse rod magazines and also cooperates with a terminal switch. The loose steel pins 115, which cometo'bear upon a board, are raised during lowering of the nail ledges 113. On the other hand, those steel pins which are located over a gap between neighboring boards enter into such gap. During a subsequent retraction of the support arms 106, until reaching their rearmost position 111, the boards are prevented from carrying out a retraction movement owing to the dropped pins; they drop in series by a certain distance or height, which is equal to the thickness of the carrier arms plus a certain play, onto the already deposited board layer of the stack or upon ledges which have been deposited thereon by the magazine 114. The steel pins 115, during suchdropping movement, also prevent to a large extent any lateral sliding or displacement of the boards, in order that the stack has imparted thereto a faultless appearance.

If the stack should be made compact then, after this operation, the lifting-mechanism 116 togetherwith the stack 111 can be lowered again by an amount corresponding at least to the layer thickness. Should, however, the stack be built up with transverse separation rods, then each magazine 114 must now be actuated in order to eject-one such transverse rod. in one or the other case there can occur during'the lowering of the stack raising of the transverse rod magazine 114 and the nail ledges 113. When this procedure has been completed then the machine is again ready for the deposition of a new board layer upon the support or carrier arms 106. Terminal switches which are provided at the lifting mechanism 116 carrying the stack 111 switch-off the machine as soon as a stack has been finished which possesses a desired or certain height.

Now as soon as the measuringand control apparatus which is to be described has determined that a board layer has been formed, then it actuates an operable element, in particular a relay 25 (FIGQ8) which triggers at a sequence or follow-up control mechanism a first operation of a logical sequence of working operations for the stacking machine, wherein by means of terminal switches always the end of an individual operation can be ascertained and a further operation initiated; the sequence of operations occurs in the manner as has been abovedescribed.

There will now be considered in greater detail the particular measuringand control apparatus of this development which determines whether a-random board, which is in the process of being advanced by the transverse conveying chains 104, still has place in a layer of a stack of boards and which, in accordance with such determination, triggers the necessary operations. During the description of such apparatus reference will be made to FIGS. 2 to 8 This control apparatus incorporates means which for each unit of the displacement path of the boards 100 produces an electrical pulse. Such means can be for instance a conventional light barrier or a mechanically actuated switch. In the illustrated exemplary embodiment such embodies a proximity initiator or switch 4 (FIGS. 2, 3 and 8) which cooperates with control flags or lugs 8a which are uniformly distributed about the periphery of a disk 8. As best seen by referring to FIG. '2, this disk 8 is in driving connection with the drive of the conveyor chains 104 through the agency of a chain drive 118. The initator 4 is applied to a direct-current voltage following the rectifier arrangement 3 (FIG. 8). During each throughpassage of a control flag 8a the current circuit of the initiator 4 is closed and accordingly a relay 5 energized. The contact 6 of the relay 5 is actuated by the pulse commands of the initiator 4. By means of the rectifier arrangement 7 there is thus produced a sequence of pulses. Of course, it would be possibleto obtain an analogous generation of pulses in an electronic manner.

The measuring and control apparatus possesses two pre-selection pulse counters 27 and 30 which can be reset to null. Such possess feeler or scanning switch means which permit the infeed of the generated pulses to both pulse counters or counter mechanisms during the passage of the boards past ascanning location. Be-

longing to such scanning switch means are the scanning switch l4 with the feeler or scanning flaps 14a (the details of which have already been discussed above) as well as a scanning switch 10 with the scanning flap member 100; the scanning switch 10 with the scanning flap member 10a is associated as an auxiliary means withthe scanning switch 14 with the scanning flap member 14a since the latter, in the case of boards of for instance approximately trapezoidal shape in profile, as such are produced by a gang saw are not capable along of determining completion of the throughpassage of such board at the' scanning location. Furthermore, there is also provided an operable connection between both pre-selection pulse counters and there are also present additional components, as will be apparent from FIG. 8 and the function of the apparatus which will be considered hereinafter. There will now be considered the mode of operation of the equipment.

OPERATION OF THE MEASURING- AND CONTROL APPARATUS l. Preparatory phase, FIG. 4

The board in sector C is engaged by the entrainment cams 105 of the conveyor chains 104 and forwardly fed in the direction of the depicted arrow.

2. Beginning of the measuring operation, FIG. 5.

The measurement operation begins after the terminal switch 14 has been actuated. The terminal switch 14 closes the contact 34 via the relay 21 and the contact 39 as well as via the relay 40.

The pulses which are delivered by the initiator 4 are recorded at the pulse counters or counter mechanisms 26 and '29.

3. Measurement operation completed, FIG. 6

After the measurement throughpassage the terminal switch 10 is actuated. By means of the relay 22 it terminates the infeed of pulses by switching-off or opening the contacts 35 and 37. Furthermore, the relay 22 delivers a pulse via the contacts 36 and 33 to the null reset coil 30 of the pre-selection counter or counter mechanism 29. This pulse counter 29 therefore resets to null. On the other hand, at the pulse counter 26 there remain the already counted pulses and the subsequent pulses are added thereto. I

4. Full Stack Layer, FIG. 7

When the pulse counter 26 has reached its pulse count number corresponding to the maximum width of the stack layer, the terminal switch 10 has carried out measurement of the just passing board but such has not yet been terminated, which is indicative of an additionalboard width, then this board should no longer be brought into the stack layer which is in the process of being formed. However, the board in sector A still has place in such stack and therefore must be introduced into such stack as the last board. This occurs in the manner above described during the description of the operation of the stacking machine. Reporting of the completion of the layer is brought about by a pulse via the relay 23 and the contact 40' to the stepping switch 24 which closes the contact 32 and at the same time opens the contact 33. Upon"completion of the measurement operation and at the same time the final reporting of the layer the pulse counter 26 is energized via the contacts 32 and 36 of the null resetting coil 27 and accordingly the pulse counter 26 resets to its null position. The pulses, which correspond to the width of the board located at the sector B, are now stored how- I ever at the pulse counter 29. The pulse counter which previously operated as a storage now functions as an adding counter mechanism oradder, whereas the pulse counter 26 which previously was functioning as the cessive boards again occurs in the manner described in the precedingparagraphs 2 to 4 of this description. When there has again been reported completion of'a stack layer by the pulse counter 29 the function of both pulse counters is again reversed and the measurement occurs again according to the afore-described paragraphs 2 to 4.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly un derstood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the .following claim. ACCORD- INGLY,

What is claimed is:

1. A control apparatus for a machine for stacking boards of regular and irregular shape, the improvement comprising:

a. means for generating electrical pulses for each unit of the displacement path of the boards transversely with respect to their lengthwise direction;

b. two pre-selection pulse counters which can be reset to null;

c. scanning switch means for the infeed of the generated pulses to both pre-selection pulse counters during the passage of the boards past a scanning location;

d. means providing an operable connection between board past the scanning location the other of such pre-selection pulse counters is reset to null and until the addition counting mechanism has reached a predetermined pulse number, and wherein at the moment of reaching such predetermined pulse number;

i. both pulse counters are switched so that from that point on the storage counter mechanism functions as the addition counting mechanism and the addition counter mechanism functions as the storage counter mechanism, so that the combination of both such pulse counters is prepared for the measurements in the next working cycle,

ii. a relay is actuated which triggers in a sequence control mechanism a first operation of a logical sequence of working operations of the stacking machine.

l IF 

1. A control apparatus for a machine for stacking boards of regular and irregular shape, the improvement comprising: a. means for generating electrical pulses for each unit of the displacement path of the boards transversely with respect to their lengthwise direction; b. two pre-selection pulse counters which can be reset to null; c. scanning switch means for the infeed of the generated pulses to both pre-selection pulse counters during the passage of the boards past a scanning location; d. means providing an operable connection between both preselection pulse counters so that in one working cycle one such pulse counter operates as an addition counter mechanism and the other pulse counter as a storage counter mechanism, in that after interrupting the infeed of the pulses - which is comparable to the passage of a rear edge of a board past the scanning location - the other of such pre-selection pulse counters is reset to null and until the addition counting mechanism has reached a predetermined pulse number, and wherein at the moment of reaching such pre-determined pulse number; i. both pulse counters are switched so that from that point on the storage counter mechanism functions as the addition counting mechanism and the addition counter mechanism functions as the storage counter mechanism, so that the combination of both such pulse counters is prepared for the measurements in the next working cycle, ii. a relay is actuated which triggers in a sequence control mechanism a first operation of a logical sequence of working operations of the stacking machine. 